Biofouling has significant impact on shipping industry. Biofouling on the hull of a vessel results in increased overall surface roughness, which leads to an increase in hydrodynamic drag. The associated costs include increased fuel consumption, labour costs of cleaning a vessels' hull, as well as removing and replacing damaged paint, in addition to costs associated with the downtime required for such services. Studies have found that biofouling may result in a 10% increase in a vessel's drag, which in turn results in a 40% increase in fuel consumption.
Existing antifouling solutions include tin and copper compounds added to a vessel's paint coating. These compounds are inadequate as they leach out of the cured paint coatings, resulting in limited prevention or reduction of biofouling. Further, these compounds may be harmful to aquatic life. Removal of biofouling material often requires mechanical efforts, as well as painting and refinishing. Such efforts require docking the vessel, and in some cases dry docking the vessel, resulting in costly downtime.
Zwitterionic materials have drawn the most attention due to their excellent biofouling properties, which are attributed to their strong hydration capacity due to the electrostatic interactions between zwitterions and water. Such zwitterions have been anchored on to polymers, such as polyacrylates, to develop surfactants, foaming agents, and demulsifying agents. However, the methods to make such zwitterionic materials are expensive and time consuming. Thus, simple and energy efficient methods to prepare zwitterionic compounds, especially from available biomaterials, are desired. Lignin-based zwitterionic compounds are an attractive alternative to these surfactants since lignins are abundantly available, inexpensive, and require simple chemistry.